old dog 23 Posted February 5, 2012 Share Posted February 5, 2012 Presently running 91 RD690S with 300-7sp, dump body. Want to replace something that will ride better, but don't want tranny that must shift much more than 7spd. Considering 2005 CXN613 with 380-6sp, 3.86 gears. Have heard rumors that these engines have had cam problems. Also anyone know how the power of the 380 compares to my EM-7 300. It has tons of torque, but not a lot of speed because it has 5.73 gears. I would like a little more road speed.Would consider granite or ch, but can't find these with air ride and less tranny speeds than 8LL. That might work, but I think the T306 6 speed would be less shifting. Several CXN613s are available with 6 spds.Would the 6spd. have enough low end for occasional offroad? Quote Link to comment Share on other sites More sharing options...
slpwlker Posted February 5, 2012 Share Posted February 5, 2012 I think if you don't want to shift you need to get an automatic. the 355/380 I drove in a ch was great in a tractor with the single stick 6 was alot better then the 5 speed. Quote Link to comment Share on other sites More sharing options...
hatcity Posted February 5, 2012 Share Posted February 5, 2012 Air ride on a dump is not as good as you want. IF you are only on hard, flat sites, it's not that bad. Occasional off road, you need hard,flat. Air is a nice ride, but lean alot. Even when empty, they lean some on a corner. Worse if loaded or dumping at a slight angle.This is what I run. 50 yd box but never near wt, capacity. Its all volume.Having the tag axle all the way back, I can level out truck when dumping, but I have off loaded with the boom several times. Quote Success is only a stones throw away.................................................................for a Palestinian Link to comment Share on other sites More sharing options...
Underdog Posted February 6, 2012 Share Posted February 6, 2012 I don't want to step on any toes, I am far from being an expert, but will someone please explain why air ride on a dump truck is wrong? I pull a 40 ft. spread axle dump trailer all on air and simply drop the bags on tractor and trailer when dumping, negating any instability issue of the airbags. I would think you could do the same with a dump valve on a straight truck.Gregg Quote Link to comment Share on other sites More sharing options...
Rob Posted February 6, 2012 Share Posted February 6, 2012 I don't want to step on any toes, I am far from being an expert, but will someone please explain why air ride on a dump truck is wrong? I pull a 40 ft. spread axle dump trailer all on air and simply drop the bags on tractor and trailer when dumping, negating any instability issue of the airbags. I would think you could do the same with a dump valve on a straight truck.GreggNothing wrong with it and you compensate rightly by dumping the bags. The biggest drawback to air ride in soft ground is tractive effort and articulation of the drive axles. Air ride just doesn't keep the tires planted as well as springs either being Mack camelback, or Hendrickson. These have been proven time and time again to be superior to air ride in this application. You can't beat air ride on highway for the ride comfort and quality but I don't think it was ever designed for day in and day out dump truck usage in off road conditions. These of course are just my thoughts.Rob Quote Plodding along with no job nor practical application for my existence, but still trying to fix what's broke. Link to comment Share on other sites More sharing options...
GreenGiant2 Posted February 6, 2012 Share Posted February 6, 2012 right on rob. Quote We the unwilling, Lead by the unqualified, are doing the impossible, for the ungrateful. Link to comment Share on other sites More sharing options...
bulldog man Posted February 6, 2012 Share Posted February 6, 2012 Amen Brother Rob !! Took the words out of my mouth . Quote You Cant Fix Stupid. But You Can Numb It With A Sledgehammer. Link to comment Share on other sites More sharing options...
lucerne tractor Posted February 6, 2012 Share Posted February 6, 2012 I had a Freightliner SD dump with heavy rears and heavy air suspension. The truck worked great. I have seen air ride dump trucks with lighter suspension in front of me going down winding roads that I let off thinking they were going to roll. 40 suspenion on up works good,46 great, and you can dump the bags when dumping.8LL is a dump truck transmission, it give you a a low hole to take off on steep grades and a couple reverse gears, one very low that will save clutches and nerves. They really are a 9 speed since you don't go back to the low hole and don't need it to take off empty or on flat ground if loaded and have low enough rears. They make a 8LL OD and a 8LL the OD has a U pattern,4th where 3rd should be and 3rd where 4th should be, the std 8LL is just an H pattern. I would get a trans with a low reverse option and a low hole since a dump truck you are going to be off road and will be backing in bad spots and backing a long ways.. Even an 18 spd is just an 8LL with a splitter, you don't need to shift 18 or even all 8. As far as chatter when backing up, with my rears locked and a RD688 with camel back rears locked, I could back up loose hills further and smoother, the camel back would hop, and the empty ride, you will praise the airbag gods. Quote Link to comment Share on other sites More sharing options...
Underdog Posted February 7, 2012 Share Posted February 7, 2012 I had doubts about my CX when I first got it for all the reasons you mention, Rob. The MH I had prior was Mack axles on camelback. However, the CX (spicer DS40 axles) has proven to be a good all around truck on and off road. The one thing I would change is the super-10 transmission. A pleasure to drive on the highway, but a lower starting gear and top end splits would be nice. I don't get in too deep, but do my share of landfills and as long as I keep good drive tires, no towhooks required.Gregg Quote Link to comment Share on other sites More sharing options...
unclebilly Posted February 8, 2012 Share Posted February 8, 2012 Why not consider an 18 speed? You don't need to use 'em all.Running empty, I use the cheater gear and high range only. With a load, I usually start in 3rd and only split in high range. Quote Link to comment Share on other sites More sharing options...
Underdog Posted February 8, 2012 Share Posted February 8, 2012 Why not consider an 18 speed? You don't need to use 'em all.Running empty, I use the cheater gear and high range only. With a load, I usually start in 3rd and only split in high range.The 18-speed is a possibility, now that I have the truck off the road for other repairs. I always said I would change out the super-10 if it ever gave any trouble, but the trouble is, it ain't broke yet !!! Besides the lack of available ratios, the super-10 is basically bulletproof, 1.3 million miles and counting...Gregg Quote Link to comment Share on other sites More sharing options...
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